Process of color photography



Nov. 14, 1933. I M. MARTINEZ 1,935,477

I PROCESS OF COLOR-EKOTOGRAPHY Filed Feb. 25, 1.930

Jwuentoz Patented Nov, 14, 1933 PATENT OFFICE 1,935,417 mocsss or cocoamorooasrny Michele Mai-tines, London, England, assignor to A. H. Johnson& -Co.'(Paper) Limited, London,

- England Application February 25,

1930, Serial No. 431,210, I

and in Great pram July 15, ms

1 Claim. .-(o1. 95-2) The invention consists in removing the colorelements in the parts of a color photographic. surface which have notbeen afiected'by light, any black silver formed by development being re-6 moved wholly or in part either simultaneously with, or subsequentlyto, the other removal. I In accordance with the invention color ele-,ments may be combined with light-sensitive layers or emulsions invarious ways and forms, 10 namely: (a) The light-sensitive layers oremulsions themselves may contain color media diffused throughout ordissolved in them; by color media I mean either substances actuallycolored or po- 16' tential colors, that is to say substances, colored orotherwise, which will change or acquire 'or produce'a color on suitabletreatment.

Y (b) The light-sensitive layers or emulsions may contain in suspensionfinely subdivided or grain- 20 like particles of one color or of morethan one color, whether such particles are actually themselveslight-sensitive or not.

(c) The light-sensitive layers may contain a color medium diii'used ordissolved throughout as 25. in (a) and particles of one or more othercolors S p nded in them as in (1)). (d) The light sensitive layers oremulsions are 7 provided with a separate layer containing ditfused colormedia or suspended color particles 30. under or over them, or both.

Photographic materials provided with color elements in any of theseforms are, after exposure in a camera, and simultaneously with ors'ubsequentto, development or fixing or both,

Id treated in a way designed to remove the color particles which havenot been aflected by light or the color media or particles immediatelyadjacent, over or under the parts which have not been affected by light,the light-sensitive ele-.

'40 ments themselves aiiected by light being,afterwards orsimultaneously removed wholly or in The object is attained by hardeningin a known manner, simultaneouslyv with, or subsequently to,

' development, the gelatine corresponding with the.

exposed parts, and then dissolving .by means. of .hot water, acids oralkalies the'gelatine parts leit unhardened, when also the color mediaor particles there present will be removed together with the gelatine,or thdse lying beneath in separemove the gelatine itself, its hardeningbeing suflicient to retain-in, over or under the parts that are hardenedcolor media, particles or potential colors; because such hardeningprevents or considerably retards the penetration of agents, so whethersimply water or appropriate solvents, which may be applied to dissolveout of the softer parts, such color, media, particles or potentialcolors.

, and cinematography, in the manner described.

As instances of some color particles which can be used as hereinbeforementioned I will name colored salts of silver, such as silvererythrosinate, silver ferricyanide .or silver chromate; colored salts ofmercury or of mercury and silver; other metallic colored salts, such asnickel dimethylglyoxime or copper benzoin-oxime; colored sulphides andoxides; the special sulphide of cop- 80. per known as copper-indigo;cmruleum; cobalt blue; Thnard blue; other mineral colors; metallicresinates and the like, especially those which are likely to combinemore or less completely with, or to be adsorbed by silver halides.Colcred, particlescan also be made from animal or vegetable colorlngmatters, such as byprecipitating with alcohol'aqueous solutions ofwater-soluble dyes and dextrin or gum arable, or both, or

by precipitating with water alcoholic solutio of spirit-soluble dyeswith or without such or r as dammar, guiaicum orinastic. Color elementsto be applied as'diflused coloration in any suitable medium or in thesensitive layer itself may be furnished by solutions'in appropriatesolvents of coloring matters or dyes suitably selected from among those,the composition of which is not such as to destroy or hamper thesensitiveness and permanence or capacity for development oflight-sensitive compounds and at the same time are not themselves delstroyed ,cr aifected in any unrequired way by the chemicals usually usedin photographic treatments. For instance, for red, pure cai'mine inammonia ,solution. erythrosine, iodo-eosin, all quinolinfe 7601013 andseveralofthc alizarine derivatlveszf for yellow also alizarine andquinoline colors, tartraaine, carthamine and many others;

for blue, compounds derived from loswood and indigiitin, alizarine blueand sevno eral more; besides others already mentioned as suitable forcolored particles. I

Potential colors, in the meaning previously explained, may be furnishedby any compound, salt, extract or other substance which may be made toyield a color reaction or preferably a colored precipitate of therequired hue. For instance a nickel salt which may be treatedsubsequently with dimethylglyoxime or other reagent, or vice versa; acopper salt which may be treated subsequently with benzoin-oxime, orvice versa; benzidine; logwood extract; ferric salts; .ozandfi-naphthylamine; leuco-compounds; uranium salts and many others.

The invention may be carried out in a number of ways, which may begrouped in a few.

to be considered as types and several varieties of each type. v

'The accompanying drawing represents cross sections through supportscoated with various materials and are drawn to an exaggerated scale.

Class A.-Embodiments wherein color media are diffused or suspendedthroughout several layers of sensitive emulsions coated on both sides ofa thin, transparent support.

Example 1.A thin film of celluloid or other transparent cellulosematerial S (Fig. 1) is coated on one side with an ordinary emulsion El,rather slow in comparison with that used for the coatings which are tobe applied on the other side, and thinned by addition of 40-50 per cent.of its volume of a saturated solution, in aqueous gelatine of! per cent.strength, of the dye, mainly used as indicator, known under the name ofBrilliant cresyl blue. The addition of this dye to an emulsion willreduce the speed of the emul- *sion, which must be taken into account.In a slightly alkaline medium, such as a silver bromide emulsion, thedye mentioned is yellow, and remains ,yellow until an acid bath isapplied, in which it changes to a good blue. The other side of the filmis coated firstly with an ordinary fast silver bromide emulsion E2,thinned by' addition of 30-50 per cent, of its volume of an aqueoussolution ofplain gelatin in which, while it'is hot, there is dissolvedas much tartrazine and quinoline yellow asit can dissolve; this emulsionis rendered ortho-chromatic by the addition of the usual sensitizers foryellow and green. Over this layer there is coated a second layer E3,which is an ordinary silver bromide emulsion thinned by addition of40-60 per cent. of itsvolume of a saturated solution of erythrosine inwater containing also 7 per cent. of gelatin; this emulsion is madered-sensitive by addition of the usual sensitizers for the red end ofthe spectrum, and is the fastest of all the emulsions used in thisinstance. The usual hardening agents may be added to the presentemulsions. The material is exposed in a camera with the surface bearingthe single layer E1 facing the lens. On exposure, the layer E1, being anordinary emulsion, is affected only by white and blue rays and by theblue components of the green rays,

while E2 is aifected by white rays, green rays and yellow rays; shouldthis E2 be also red-sensi-,

tive, which would do no harm, it would be affected also by red rays.Blue rays would not afiect this emulsion because they would be absorbedby the yellow color of the El emulsion. The layer E3.

will be affected by white rays and red rays-only, because the blue rayswill not reach it, and to yellow rays it is not sensitive. The crossedparts in Fig. 1 show where the layers are afiected by .the light rays,indicated at the left hand of the figure, where Wh stands for whiterays, B for blue rays, G for green rays, Y for yellow rays, R for redrays and Bla for black or no rays whatever. The treatment to be appliedto this material is development in any of the usual ways, and then theapplication of such a bath as is already kdiown to have the effectoihardening the gelatine of.

an emulsion in the parts wherein blast: silver has been developed.Developers are also known which, in one single treatment, produce boththe development of the, exposed parts and at the same time the hardeningthereof. The pr ferred prescription is the following, made in two steel:

l Equal parts of the first and the second solution are mixed for actualuse. After this bath the material is transferred to a bath of warmwater, or to a cold bath of an acid, wherein all I the gelatine parts oithe emulsions which have not been affected bylight, the silver halideremaining therein and the colorations also contained therein, are alldissolved and there remains a negative picture in black which retains acolor picture in itself, see Fig. 2. It is now sufficient to transferthe picture to a bath, made according to any of the known prescriptions,for the purpose of reducing and dissolving black silver, such as acidpermanganate, acid persulphate or hypo-ferrloyanide, the picture being'kept in the bath until thecblor picture is plainly visible. The blacksilver can be removed entirely, or, preferably, can be removed onlypartly, according to taste, it being always advisable to leave a littleof the black silver so as to soften the briiliancy of the colors. In theacid reducing bath or'in a subsequent acid bath the dye in E1, where itremains, is changed to blue.

The picture obtained in this way is a peculiar one, inasmuch as it is anegative insofar as the blacks and the whites are concerned, but is apositive insofar as the colors are concerned, although the luminosity ofthe latter is inverted;

that is to say in this negative, whilst the blacks will appear white andthe whites will appear black, a pale blue will be represented in adarker shade of blue and vice versa, and so for all colors. 01' course,in printing on a material of similar characteristics the black andwhites and the im- 1 ers oi sensitive emulsion, coated on one side onlyof a support, potential colors being most suitable for use in thisclass.

Example 2.-A transparent support 8 (Fig. 3) which may be celluloid,other cellulose film, glass, paper or the like, is coated firstly withan emul sion E1 which is panchromatic and contains such an agent,preferaby colorless, as will give a red color or red precipitate onsuitable treatment, for instance either a nickel salt ordimethylglyoxime or e-benzildioxime. The nickel salt may be dissolvedthroughout the emulsion or suspended therein, ior instance in the formof a carbonate or a phosphate. This layer of emulsion, as indeed allother layers, may be extremely thin so that all the layers takentogether are hardly any thicker than a single ordinary emulsion, becausethe function of those layers is simply to retain colorations or theagents therefor. Over the first layer there is applied a second layer ofemulsion hi2, faster than the preceding one and ortho-chromatic andcontain =1. in suspension or difiusion, an agent which will give ayellow coloration or precipitate with a suitable reagent; for instanceammonium molybdate, which will give a yellow precipitate on treatmentwith a phosphate; or a cobalt salt which will give a yellow compoundwith an all nitrite; or a uranium salt which will give a yellowprecipitate with an alkali carbonate. Over this layer there is coatedagain a third layer of emulsion E3 which this time is only an ordinaryone and is faster still than the preceding ulsio'ns. This layercontains, in suspension or difiusion, an agent which will give a bluecoloration or precipitate under suitable treatment: for instance asolution oi benz idine, which will give blue on treatment with potassiumferricyanide or other color developer; or a solution of logwood extractor haamatoxylin, which will give a blue precipitate with ferric salt orsome other salt. Over this emulsion there is coated still another layerE4 of the same ordinary emulsion, that is of the same speed as'ES, butspecially intended for producing a contrast. This last layer contains Ja mixture of all the agents alreachl used in the previous emulsions. Thematerial so composed is to be exposed in an ordinary camera, preferablythrough the support side, that is with the "glass or celluloid facingthe lens. In Fig. 3 the crossed parts in each emulsion represent theparts which would be afiected by light rays indicated to the left handof the figure. There must be noted the gradations of the affected parts,which gradations are producedby the resistance to the penetration of therays oflered by the several layers, and by the different colorsensitiveness or the layers themselves. A compensating filter or anasculin filter may be used in the lens.- After exposure the material. isdeveloped and hardened, preferably in the developer bath described inExample 1, the hardening being applied for the purpose of retaining inthe hardened parts the various agents cmbodied in the emulsions. Actualremoval of the gelatine in the unhardened is optional, asthevariousagentscanbesoembodledastobe washed away by water, or bysuitable agents, applied afterwards, or simultaneously. In most cases,however, the soda of the bath recommended as developer is sufllcient toextract and dissolve all the agents mentioned. from the parts or thegelatine that are not hardened. After this operation all the variousreagents mentioned, which are for the purpose of developing the col- 7orations, are applied either in the form of a bath, or by'application bya brush, or by cotton wool. These reagents may be mixed together or usedseparately. It is preferable first to apply the various reagents in asolution in which they are all dissolved together, and afterwards to ap-5 ply separately any one which may be required to enhance a particularcolor everywhere in the picture, or only locally in parts thereof. Fig.4 shows the parts where the color reaction would be obtained; for itmust beobservedthat, although all the parts which are crossed in Fig. 3have been hardened, the color reaction can only happen where each layeris left uncovered by the superimposed layerss The emulsion E 1containing all agents, will yield black where the 90 agents are left.This emulsion could also be used without any agent, relying for black onleaving some reduced silver, which ispresent at that point in thelargest'quantlty. It is now sufflcient to remove wholly or partially theblack silver to obtain a clear view of the color picture, which is anegative in the blacks and whites and a positive in the colors. Theremoval of the silver may occur before, or simultaneously with, thedevelopment of the colors. 1 86 By inverting the order oi the layersgiven in this example and their relative the material could be used forexposure from the coated side, in which case the colors could bedeveloped in the parts left soft, soon after, or other 195 with,development and hardening.

Example 3.-As an instance oi how typical example maybe varied I willoutline an em o ment wherein some of the characteristics c4 EX- ample 2are combined with some oi the characteristics of Example 1. A support iscoatedwith a first layer of a red-sensitive emulsion containing an agentfor red as mentioned in the preceding example; then withanortho-chromatic emulsion, containing an agent for yellow as mentionedin Example 2, and lastly with an emulsion ex:- ectly like the E1- ofExample 1. Treatment to be applied is development and hardening of theex-' posed parts, and then development of the colors in the partshardened; this treatment will only act on the first two emulsionsbecause the last one has no potential color and only changes its yellowcolor to blue in an. acid bath. Such a material would yield a picturethat is a negative in the blacks and whites and a positive in thecolors.

Various other sequences of layers and ways of grouping are possible withpotential colors; for instance in Example 2 emulsion 154, Fig. 3, can

be made the slowest and emulsion E1 the fastest,

exposure of the material being made with the g;

coated side facing the lens. This variation would be specially suitablefor coating papers iii-'- tendedto beewlththe coated sideagalnst a firstpicture, obtained by camera exposure of material prescribed in- Example2. 3;

Instead of potential colors, such coloredparticlesmaybeusedinthformofsalts in the emulsion, as may be dissolvedby any appropriate agent, in which case it is not necessary to removethe gelatine. when this is the case,

its,

" the hard parts; in this case dextrin or gum arabic or glycerine neednot be added to the emulsions.

Variation to Class B One most important variation is also possible whenpotential colors are concerned. This consists in coating a support, suchas paper or the like, with the reagents that are required to produce thecolors in a material, such as for instance that described in Example 2.The reagents may be applied to the support in a suitable medium, forinstance gelatine, gum arabic, dextrin or the like. Paper or othersupport bearing on its surface the various necessary reagents all mixedtogether, may be dried and kept for use when necessary. I will call thisa positive reactive paper. The potential color photographic material,for instahce that described in Example 2, is developed and hardened inthe developed parts as described, and then the agents or potentialcolors contained therein are dissolved from the soft parts oi thegelatine; no actual development of colors is applied. it sheet of thepositive reactive paper is brought in contact with a material made asdescribed in Example 2 while the latter is in a wet or damp state, thecontact being maintained, preferably under pressure, for a short time,with the result that the color reaction will then occur between thematerial of Example 3 and the paper, and the color picture will appearon the latter. Thus prints may be obtained simply by contact, withoutusing light-sensitive layers or resorting to exposure to light or anyother treatment, except perhaps the washing in plain water of thepositive reactive paper for the purpose of dissolving any reagents lefttherein. Only a limited number of copies could in this way be obtainedfrom one picture, according to the quantity 0! agents incorporated inthe layers of the material of Example 2, or or any other example, inaccordance with this invention, suitable for the purpose.

It should be added that, generally, the addition of the various colormedia slows down to the required degree a fast emulsion, so that itwould be advisable, when practising any of the examples given, to startfrom a single emulsion and to divide it into so many parts as are thelayers to be coated on a support, and then to make to each part of thenecessary additions.

Also it must be kept in mind that 'the color media must not necessarilybe incorporated in the emulsions; they may be applied as separatecoatings between or over or under the relative layers of emulsion, whenit will be found that they interfere less than otherwise with thesensitiveness and selectiveness of the emulsions, especially ii alcoholis used'as a medium for the sap-=- arate coating or" color media.

Finally, whenever, in any embodiment of the present invention, severallayers of emulsion and color media are to be applied on a singlesupport, separate supports may be used, instead, for any or each of theseparate layers of emulsion or color media, and the various supports, socoated, may be used all together in the form of a pack, orin any othersuitable way, andthey may be separately subjected to the necessarytreatments.

Having now fully described the nature of the said invention and the bestmeans I know oi carrying the same into practical effect, I claim:-

A process of color phot aphy which consists in coating 9. surface wit atast one photo-sensitive layer containing otential colors, then exposingthe coated surfac to the action of light, then removing potential colorsfrom those parts which have not been affected by light, and thenapplying the surface to a. support containing at least one agent adaptedto develop the colors required from; the potential colors remaining onthe surface.

MICHELE MARTINEZ.

Hill

